Devices for moving objects such as aircraft canopies



Feb. l2, 1957 c w. MUssER ETAL 2,780,961 DEVICES FOR MOVING OBJECTS SUCH As AIRCRAFT CANoPIEs Filed May 7, 1953 2 Sheets-Sheet l FIG.5

Feb. l12, 1957 c w. MussER E'rAl. 2,780,961 DEVICES FOR MOVING OBAJECTS SUCH AS AIRCRAFTCANOPIES l Filed May 7, 195s f2 sheets-sheet 2 4 J 1" FIG 3 v 1753 Plas 38 r 4Q 12.10 12 56 42 76 65 6l 54 W 7U 12 ZZ INVENTOR. c wALToN MussER FRANcas w. mason-i nl." MLM ATTORNEYS:

FOR MOVING OBJECTS SUCH AS AIRCRAFT CANOPIES C Walton Musser and Francis W. Detsch, Philadelphia,

Pa., assignors to the United States of America as represented by the Secretary of the Army Application May 7, 1953, sei-iai No. 353,701

11 claims. (ci. s91) (Granted under Tine as, U. s. codemsz), sec. 266) Y DEVICES altitudes is the problem of providing for the safe exit of the pilot, and others aboard, at time of emergency during llight. In airplanes of .this type, bailing out (i. e., abandoning the airplane during ilight) can no longer be performed as it was in the past. In most aircraft llown today, the action'ofr speed-generated forces on ying personnel makes emergency exit during iiight extremely diicult, if not impossible, unless done by some means providing for forcible ejection.

As a result, emergency exit from airplanesnow'in use resolves itself into two basic operations: lirst, the canopy must be very rapidly moved from the cockpit opening; second, the pilot must be forcibly ejected from the airplane through that opening.

Those skilled in the art know of the enormous forces which act on an airplane canopy, even when fully closed, as the craft is flown and maneuvered at high speeds. Even though the canopy be streamlined those forces act in'many directions simultaneously, sometimes tending to 4 Yforce the canopy open, sometimes tending -to hold it closed, sometimes tending to move it sideways of the airplanes fuselage. It is therefore obvious that opening the canopy can not be satisfactorily ei'ected by the pilots own strength, because many times the pilot is unable, for one reason or another, quickly to move .the canopy sufficiently far lto Iallow his exit from the airplane.

Successful opening of .the canopy during ilight requires a very quick acting device because, once started, even if open only -a very small amount, the action of the abovel mentioned Vforces may become much stronger. In fact, with 4slowly operating canopy moving devices, canopies have been known to break into pieces and be torn from the'airpl'ane during opening, with resulting injury to aircraft personnel.

To build a purely mechanical or electromechanical canopy opening device to furnish sulcient energy to open the canopy quickly under all conditions likely to be encountered would require a prodigiously large, expensive and heavy mechanism.. This, of course, is prohibitive in aircraft equipment. Our present invention, however, satisfactorily fulfills all requirements including the minimization of weight and bulk which is so objectionable, by embodying chemico-mechani-cal principles presently to be explained.

v iForcible ejection from the .airplane is presently practiced in many well known manners which form no part 2,780,961 Patented Feb. 12, 1957 to the seat occupied bythe pilot. When emergencyv exit from the airplane becomes necessary, the Vcatapult is activated to eject forcibly the seat and the pilot thereinfrom ythe airplane through the previously -uncovered Vcockpit opening. i

ln essence, Vour novel device comprises an outer tube closed at one end, but open at the opposite end.n Slidably litting inside the outer tubes open end is an inner tube also closed at one end, but open at the opposite end. In fitting together, theA inner tubes closed end extends beyond the-outer tubes open end; therefore, the closed ends ofthe respective inner and outer Itubes form the longitudinal extremities of our device.

VSlidably accommodated in the inner tubes closed end for radial movement into and out of locking engagement with the outer tubes open end are a plurality of latches. When these latches are in locking engagement with the outer tube no appreciable relative axial movement between the inner and outer tubes is possible, however, rotational freedom between those tubes is possible; but, when the latches are not in locking engagement with the outer tube, relative axial movement, as well as rotational freedom, between the tubes is possible. Y

` The latches are moved out of locking engagement with the outer tube by the vmovement of a firing pin with which 'they are interengaged. This tiring pin is also slidably accommodated in the inner tubes closed end, and, subsequent to moving the'latches out of locking engagement with the outer tube, also serves to detonate an explosive cartridge contained within the inner tube.

Movement of the ring pin so as to cause movement of the latches and detonation of the explosive cartridge results from the action on the firing pin of energy supplied in fluid form to our device from an external source.

Detonation of the explosive cartridge supplies suflcient energy to cause relative axial movement between the inner and outer tubes.

At installation of our device in the airplane, the outer tube is mounted upon a base slidably supported on'guide rails forming part of the airplane structure, while the inner tube is attached to the airplanes canopy and is also connected to the means mounted in the canopy for supplying energy to our devices firing pin. This energy may, preferably, be in the form of a liquid or a gas, although mechanical means could also be used for furnishing energy to the tiring pin. This manner of installation allows the canopy to be opened and closed in the usual manner to permit normal ingress and egress of the pilot before and after ilight.

When it becomes necessary to move the canopy from the cockpit opening during flight in preparation for emergency exitV from the airplane, the iiring pin within the inner tube is energetically moved, as by hydraulic vor pneumatic force, against the explosive cartridge contained within the inner tube. However, before `the tiring pin strikes the explosive cartridge, initial movement of the pin causes the latches to move out of locking engagement with the outer tube so that the inner and outer tubes yare thereby no longer locked together against axial movement rela-tive to eachother. That done, the firing pin then detonates the explosive cartridge. Gas pressure resulting Itherefrom then builds up within the catapult practically instantaneously and forces the inner and outer tubes to move apart from each other in an axial direction. During this action, the canopy attached to the inner tube is quickly and positively moved from the canopy opening, thereby providing an avenue for subsequent exit of the pilot from the airplane.

. One object of our invention is to provide a device for quickly and positively moving the canopy from the cockpit opening ofk an airplane when emergency exit pose mentioned whose operation results from the action Y fon the devices tiring pin of energy supplied-in Huid form. A still further object is Vto provide a devicerfor the vaforesaid purpose in whichinitial movement of the tir- '.iing pin serves to unlock the Ydevice vfor subsequent operatiomand terminalrmovement of the same ring pin servesto detonate an explosive cartridge for supplying v sucient energytov cause the devicesoperationand consequent removal of the canopy from the cockpit opening. Theforegoing and other objects ,and advantages of our invention will becomevapparent from an inspection Yof the following ydescription 'and the accompanying draw- -ings -which describe and show, respectively, Voneem- .bodiment of our invention installed in an airplane. v,It :must be understood, however, that this embodiment and :practical application .have been chosen for illustrative purposes only, and that other modified and varied em- '.bodiments `and practical applications are feasible without departing from the spirit and scope of our original concept.

In the drawings: .1Fig..l is a side view, in light solid'line, of a portion -of the fuselage of a representative airplane, .including the canopy, showing our device installed. .The canopy -=.isindicated to be in the closedposition by broken line,

and to bein the partially open position by light solidV -,line. VHowever, as will be'explained later, this movement of the canopy' is not eiected by the operation of 'our invention.

.'Fig. Zis similar to Fig. l, but movement of. the canopy "here is being effected by the operation of our invention.

Fig. 3 is a side view of our inventive device, dismounted vfromlthe airplane, partly broken away and partly sectioned to expose most of the devices components.

Fig. 4 is a partial vertical cross-section taken along line 4 4 of Fig. 3 to show internal construction and positional relationships existing between components rfwhen the devices tiring pin is in what we shall refer to l.as the retracted (i. e., in readiness for ring) position. -'For convenience of drawing, it has been assumed that f Fig.. 3 was not partly broken away and partly sectioned ,as shown in Ythat figure.

' Fig.- 4A is'similar to Fig. 4, but shows positional-relationships'existing between components shortly after the tiringV pin' has moved to what we shall refer to as the firing position (i. e., to the position causing detonation of the devices explosive cartridge), and, shortly after the innerand outer tubes 'have begun to move axially apart..`

Fig. 5 is -a vertical cross-section taken along line 5--5 vvot"Fig.-`4. to show additionalrdetails of internal constructionl andof positional relationships existing between comi Vponents while thefiring pin is in the retracted position. -'For` completenessV of drawing, the right half of this g- -"urehas been added, but those familiar with reading 'drawings know that,rtechnically, this right half would not actually be seen in a section along line 5-5 of Fig. 4. Fig. 6 is a horizontal cross-section taken along line 6-'6 of Fig.Y 4 toshow further details of internal con- -struction and of positional relationships existing between components when the ring pin 'is in the retractedy posi ftion. vFor the samereason stated in'connection with Fig.` 5,V the lower half of this'gure has been added.

YV"Fig 6A is similar to Fig. 6, but shows positional re- "lationships' existing between lcomponents. afterv the'r- .ing kpin has been move-d to the tiring position.

"Figf7` is a horizontal cross-section taken alongline 7-7 of Fig. 4 to show more details of internal con struction and 'positional relationships existing "between components when the firing pin is in the retracted posi tion. For the same reason stated in connection with Figs. 5 and 6, the lower half ofthis figure has also been added.

Outer. tube, lower. cap, bearing tube, and stop. ring The basic structural member of ,our invention is the outerY tube 10,(see Figs. 1 to 7). This tube isV externally threaded at the lower. end 11 (i. e., toward the bottom of the drawingsheehasshown in.:Fig. 3).and.is internally threaded at its upper end 12 (i. e., toward the top ofthe drawing sheet, as-shown in Figs. -3:.to 5).

Threadedly attached totheexterior` of the outer tubes lower end in sealing relationship thereto is the lower cap 13 (sce'Figs. 1104.3). Projecting from the closed end 14 of this cap is the lug 15 through which extends .theopening 16 (see Fig.3). .This opening isprovided for laterzpivotally. mounting the outertube inthe vair- `plane,.although that tube mayalsobe mounted in the airplanelin any convenient'manner other than byv azpivotal connection.

' Threadedlyattached to the interior of the outertubes upper end, also insealing relationship thereto, is theV externallyf'threadedbearing tube 17 (see Figs. 3 to' 7). This tube is seatedeinthe outer tubes upper end, and is supported. substantially concentrically within that tube. Asshown in Figs; 4, 4A and 5, the bearing tube .is provided interiorly. with. the three concentric bores` 18,19 and 20, in the rst namedof which Vthe helicalsealing member 21is located. in an accommodating helical groove.

Alsothre'adedly attached to the interiorof the. outer `'tubes upper end is the stop ring 22 (see Figs. 1'. to 5) .havingfthebore'ZS (see Figs. 4, 4A and .5) which' is substantially continuous with the bearing tubes bore` 119. vExteriorly, the stop ring is provided with the flange 24 which is seated against the outer tubes upper end (see Figs..3v to 5).

Y Inner-tube, circular-retaining spring and'spacersleeve tubes bore.

`VInsidetheinner tube is ak spacer sleeve 32(see Figs. 3 to.5), `itsupper end snugly secured therein, and .its lower end 33. conveniently reduced in diameter to lt inside the circularretaining `spring (see Fig. .3). There is thusformed .injthe spacer. sleeves exterior surface theshulder. 34 .which .limits thaty sleeves insertion into y the nnentube.

y Explosive cartridge, pleugiam upperV cap Contained partly inside the inner tube andpartly inside I the spacer 'sleeve is the explosive cartridge 35 (see Figs. 4, 4A and 5 Theparticular construction and Vmodeof operation'of this cartridge does not forme' par-t of the presently discussed invention, but, for convenience of explanation, various of vthe cartridges components will be mentioned as the description of our inventionproceeds. In the. above named figures it can be-seen that the body ,portion 36 of thecartridgeis contained within the spacer sleeve, "whilefthe scmewhatlarger diametered headfpor- .tion' 37 is contained within the inner tube. As a result vof'kthis arrangement, the cartridges head lend is seated against the "spacer 'sleeves Aupper end.

VAdjacent the explosive cartridges headportion is 'the plug 38 (see Figs.4 to 7). The body 39 of this plugfits irsidevinnertubejl and is adapted'at'the lower end. 40,

to abut the cartridges head portion and also the closing disc 41 forming part of the cartridge (see Figs. 4 and 4A). The upper end 42 of the plug is somewhat larger in diameter thanthe plugs body and therefore extends A outside the inner tubes upper end 29 (see Fig. 5).

Threadedly attached to the exterior of the inner tubes upper end is the upper cap 45 (see Figs. 1 to 7). This cap comprises the body portion 46, which is slidably rac commodated, partly in bearing tube 17 and partly in stop ring Z2 (see Figs. 4, 4A and 5.), yand the shank portion 47 which issues from the body portions upper end and extends beyond the stop ring (also `see Figs. 4, 4A and 5). As also shown in those figures, the body portionl is provided with the flange 4S which tits into an accommodating recess in the stop rings -bore 23; and, las shown in Fig. 3, the shanks free end is provided with theopening 49.` This opening serves later =to accommodate means for connecting inner tube 28 to the airplanes canopy. With the upper cap vattached to the inner tube, the plugs upper end 42 becomes accommodated in the recess 50 provided in the upper caps body (see Figs. 5, 6 and 6A).

Slidably accommodated in the diametrical-ly transverse groove 51 in the plugs upper end 42 (see Figs, 5, 6 yand 6A) and in the diametrically opposed openings 52 in the upper caps body 46 (seeFigs. 6 and 6A) are the latches -53 and 53a (see Figs. 4 to 6A).` Also slidably accombody. The latches and the firing pin will 'be described next under separate headings. l

Latches Latches 53 and 53a are substantially identical lto each .other andY therefore have been identied by the same numerical reference number. However, in order to facilitate explanation and understanding of our invention, the letter a has been vsuflxed to the numerical `reference number identifying one ofthe latches. For the same reason, each corresponding characteristic of those latches will `be identified by a reference number with respect to one latch and by the same reference number having the letter a suftixedthereto with respect to the other latch.

Referring to Figs. 6 and 6A which ,show theA latches in horizontal cross section along with other details, it can be seen that latches 53 and 53a have .the corresponding i wide outer ends 60 and 60a, the narrower 'inner ends 61 and 61a, and the still narrower intermediate portions 62 and 62a, respectively. Asthere shown the outer ends are arcuate in shape, having substantially the sameradius as that of the. bearing tubes bore 20. Thelatchesinner ends are provided with the sides 63 and 63a respectively,

and the intermediate portions are provided with the sides 64 and 64a,irespectively.. v

Notice also, in Figs. 6`and 6A, how Vthe latches intert with each other, and how the sides 63, 63u, 64 and 64a of the latches inner ends and intermediate portions respectively surround ring pin 6.

Latches 53 and 53aarecapable of Ibeing inlo'ne olf'twoV positions, both latches. being in one or the other position at any particular time. Those positions are: the locked position best shown in Figs. 4 and 6, and the .unlocked position shown in Figs.` 4A and. 6A. The latches are placed in' the locked position when our device is-assembled, andare moved to the. unlocked position, in a manner later to" be described, only'when the device is operated.

When the latches are in the vlocked position, oute'r ends, 60 and 60a of `the respective latches pass through the upper caps openings 52 and extend into the bearing tubes bore 20 (see Figs. 4 and 6). In so doing the outer ends i of the latches overlap stop ring 22 (see Fig. 4). As a coi' is possible.

Y opening.,

sequence, no appreciable-axial movement of upper cap 45, and inner tube 28. joined thereto, relative to outer tube 10 F is possible.

When the latches are in the unlocked position, the outer A ends of the respective latches do not extend into the bearthe inner tube joined thereto, relative to the outer tube,

In fact, Fig. 4A shows Isome such movement.

as having occurred.

Attention is also called to the corresponding, coplanar, arcuate, stepped in portions 65 and l65a on the lower sur- Afaces of the respective latches (see Figs. 4 and 5 to 6A). As Figs. 4 and 6 show, these surfaces lbecome continuous to create a circular recess in the latches when the latches are in the locked position. IThe purpose for this condition will be mentioned later when ring pin 56 is described.

Firing pin Firing pin 56 has the. cylindrical upper and lower end portions 70 and 71,. respectively, which are connected together by intermediate portion 73 (see Figs. 4, 4A Iand 5). The upper end portion is provided with the resilient sealing ring 73 and the lower end portion is provided with the axially located tiring tip 74 which projects downwardly therefrom. The intermediate portion comprises the parallel at sides 75 and 76 (see Figs. 5, 6 and 6A) and the beveled sides 77 and '77a (see Figs. 4 and 4A). These beveled sides diverge outwardly (i. e., away from the firing pins axis) from the bottom to the top of those drawing igures and have substantially the same slope rela tive to the firing pins axis. They are identified by the same numerical reference character, one having the letter a suixed thereto in-order `to facilitate later description. As shown in Figs. 6 and 6A, intermediate portion 72 is rectangular in horizontal cro-ss section, but because of the beveled sides 77 and 77a, the area of the rectangle vari-es depending upon where the horizontal cross section is taken. -1

Firing pin 56 is capable of being in one of two positions:

u the earlier mentioned retracted position shown in Figs. 3,

4, 5, 6 and 7;` or the earlier mentioned firing position shown in Figs. 4A and 6A. The tiring pin is placed in the retracted position at the time of assembly of our device, and is moved to the firing position, in a manner later to be v described, at the time-of operation of the device. Whenthering pin is in the retracted position, part of that pins lower end4 portion'is accommodated in the circular recess formedby the coplanar stepped in portions 65 and 65a of the respective latches (see Figs. 4 and 5). This enagement between the ring pin and the latches prevents the outer ends of the latches from moving tridge 35 is detonated. Inward radial'movement of the outer end 60 of latch 53 is caused by the action of the fring pins beveled side 77 against that latchs side 63;

and inward radial movement of the outer end 60a of the I latch 53a is similarly caused by the action of the firing pins beveled side 77a against that latchs side 63a. As a consequence of the first action, upper cap 45 and inner tube 2S attached thereto are free to move axially out the outer tube 10. Detonation of the explosive cartridge, which will be explained later, is caused by the firing pins tip 74 which passes through the opening 78 in plug 38 (see Fig. 4) and forcefully strikes the explosive cartridge. As a consequence of this action, suffi cient energy is released from the cartridgeto move the inner tubeiand the co-joined upper cap axially from the outer tube, thus moving the canopy fromy the cockpit Shear pins* Serving to prevent relative rotation between.. upper c ap ingithe'body portion 871 and thefrail shame portion 82 (see Fig. 7). The body portionrof eachshearvpinpasses through an accommodating opening inthe uppercapis body portion 46, throughy one of a plurality ofthe U- shaped radially extending castellations 83 (see Fig. 7)

iocated in the inner tubes upper end 29., and into an pins, lower-lend, portion 71.

Installation in airplane Referring to Figs. 1 and 2, outer tube 10 is mounted inthe airplane 87 byattaching lower cap 13 tothe base plate 88-in any convenient manner. Connection between the lower cap and the base plate can be accomplished throughV the use of the lower caps opening 16 so that the outertube is mounted for pivotal movement on the base plate. This base plate is slidable along the guide rails 89 forming part of the airplane structure. Inner tube 28 is connected to the canopy 90 by attaching upper cap 45 to the canopy in any convenient manner. Connection between the canopy and the upper cap can be accomplished through the use of the upper caps opening 49 so that the inner tube is connected for pivotal movement to the canopy. Next, one end of the conduit 91 is connected to upper cap 45 through the tapper opening t 92 (see Fig. 3). Referring back to Figs. l and'2, the other end of the conduit is connected to the initiator 93 conveniently located in the canopy. The initiator per se does vnot form a part of the invention being described, nor are any of the initiators elements necessary to the description of our invention. It will suice to say. that the initiator, when activated, furnishessutlicient energy, in tluid form, to cause substantially simultaneous operation of our device, in a manner later to be described;

i Although our device is mounted in the airplane.;A is connected tothe canopy, and isl attached to the initiator as just described, it does not interfere with the normall openingandv closingY of the canopy. in. the usual-manner t permit entering'and4 leaving the airplanefbefore, and after flight. For example, reiferringgtoAFig.Y l, when the canopy is movedfromits position indicated by dotted 'line in the direction indicated. by the light solid arrow 'toward' the open position (notshovvn),V it pivots about the hinge 9d mpving upper cap 45 and'.v co-joined inner tube 27S. along withit. Since no relatiyeaxialmovement between. the upper canard. the outer. tubcis. possible,

' b y virtne of the locking` engagement between latchesr53 and. 53a and thc. outer. tube., that tube is moved. along adjacent the bases 1eft end.

The particular ioteilationbcre described, dictated by. cbc Yfact that. tbecenopy is conncctcdto tirocini... .ne

J3/"hinge 94 and further. bi', the fact-thatour -deviccinust not interferewitb normal. opening and. closing. o fthc.

canopy! Although.. 'a hinged; canopy isf. shown. in.. the

'drawing gurcs. our.' invention. worlssequally well. .on those. canonieswhicb. arc. moi/ed. from.. the cockpit .opening by a rectilinear motion.

l 8 Operation` ',Whenthernecessity arises foranemergency exit from vthe airplane during ight, initiator 93 is activated to generate an energy surge. This energy passes from the initiator, through conduit 91 (see Figs. 1 and 2), through the recessf95'(see Figs. 3 to 5) and into recess 54 (also Fseeligs. 3 to 5)'. .Shear pins 80 prevent the tiring pins .immediate axial movement toward the tiring position, 'but before any noticeable .amount of time passes, the

energy builds up sufficient magnitude to cause failure of the shear pins and subsequent practically instantaneous movement of the tiring pin to the tiring position. This movement of the tiring pin-is facilitated by the axially extending grooves 96 therein` (see. Figs. 5 and 7). As the pin moves, the outer ends of. latches 53 and 53a are vwithdrawn into upper capl 45 in the manner earlier explained, then tiring tip '74 Apasses through the plugs opening 78 and strikes explosive cartridge 35. Inside that cartridge, the hammer 97 (see Fig. 4A) is moved to detonate the percussion primer 98. Fire from the primer passes through the tire holes 99 to ignite the booster charge 100. Ignition of the booster charge causes disintegration. of the retaining disc 101 and results in explosion of the cartridges main powder charge 102 (illustratively shown in stick form). When this charge is exploded the `lower end of the. cartridge is blown open (not shown) and gas pressure builds up inside the device. This pressure forces the co-joined inner tube and upper cap tomove axially out the outer tubes open end. ln so doing, canopy attached. to the upper cap isV quicklyr and positively movedfrom the cockpit opening sothatsubsequent ejection of: the pilot from the airplane may occur in well-known manner.

From the foregoing description and references vto the drawings, it will be apparent that we have provided. a device for quickly and positively moving the canopy from the cockpit opening of an airplane when emergency exit therefrom duringV ight becomes necessary; that we have provided a device ofthe character mentioned which, a1- though mounted Vready for use in the airplane, does not interfere with theY normal opening and closing of the canopy before and after ight; that we have provided a devicewhose-operation results from action-on the devices tiring pin of energy supplied in fluid form; and that we have-provided a device inV which initial movementk of the tiring-pinserves to unlock the device for subsequent operation, and terminalmovement of the same tiring pin serves to detonate `an explosive cartridge forsupplying suiicient energy to cause-the devices operation and consequent removal of the canopyfrom the cockpit opening.Y

Those skilled in the art will realize that out invention is amenable-to numerous modifications and variations in VKstructureand operation as well as to many practical applications other than that 'here disclosed without departing from the spirit and scope of our original concept. For that reason we do not wish tojbe'limited inpatent coverage to ther opposite end,` va slidably fitting open en d foremost into said rstltube, the closed end of said second tube being adaptedfor connection to the other object; an explosive cartridge in said second tube for supplyingzsufcient energy to move saidv tirstand' said secondV tubes.. axially apart so as to move thefone objectA relative to the other object; a latchin. saidA second tube forA selectively locking said first v`and said secondA tubes against. relativeY axial. movement;

a tiring pin slidably accommodated in said second tube and interengaging with said latch, said firing pin serving to hold said latch in the locking position while that pin is in a irst position, but further being selectively movable to a second position `for successively moving said latch so as to unlock said first and said second tubes for relative axial movement andthen acting on said explosive cartridge to cause release of the cartridges energy; and initiator means for selectively supplying energyto move said ring pin from the first to the second position; whereupon said iirst and said second tubes areV moved apart axially by said explosive cartridges released energy, thereby moving the one object relative to the other object.

2. The device `of claim l in which the closed end of the rst tubeis in the form of a removable cap which is adapted for connection to one of the objects.

` 3. The combination, ina device for moving a cover kfrom, an opening in an object, of: an external tube closed at` one end, but `open at the opposite end, and adapted for connection to the object; a stop ring in said external tubes open end and defining in conjunction therewith an annular groove inside that tubes open end; an internal tube slidably fitting open end foremost through said stop ring and into said external tube so as to be movable axially relative thereto through that tubes open end, said internal tubes closed end being adapted for connection to the cover; an `explosive cartridge in said internal tube for supplying, upon demand, suiiicient energy to move said external and "said internal tubes axially apart so as to move the cover Vfrom the opening; a latch in said internal tube for selec- -tively engaging with the annular groove formed by said external tube and saidstop ring so as releasably to lock Vsaid external and said internal tubes against relative axial movement; a tiring pin slidablyV supported in said ,internal tube and interengaging with said latch for holding said latch in thelocking position when that pin is in a retracted position, but for moving said latch to unlock said external and said internal tubes for relative axial movement and for acting subsequently on said explosive cartridge to cause release of the cartridges energy while that pin is moved to a ring position; and initiator means for supplying energy to move said tiring pin from the retracted to the tiring position; whereupon said external and said internal tubes are moved axially apart by said explosive cartridges released energy to move the cover from the opening in so doing. p

4. The combination of claim 3 plus a bearing tube in the external tube axially adjacent the stop ring, said bearing tube defining an annular groove inside the rst tube in conjunction with the stop ring for accommodating the latch when that latch is in the tube locking position, andV to slidably support theV said bearing tube also serving internal tube.

`5. In a device for moving a hatch cover from a hatchway in time of emergency, the combination of: an outer tube; a cap closing one end of said outer tube and adapted for attachment to the hatchway; an inner tube also closed at one end, but open at the opposite end, said inner tube being slidably supported in said outer tube for axial movement relative thereto through the outer tubes open end with said inner tubes open end opposing said outer tubes closed end, the closed end of said inner tube being adapted for attachment to the hatch cover; a bearing tube in said outer tube for slidably supporting said inner tube therein and having an internal annular groove; an explosive cartridge in said inner tube for supplying sufficient energy to move said outer and said inner tubes axially apart, thereby to move the hatch cover from the hatchway; a latch in said inner tube for selectively engaging with said bearing tubes annular groove so as releasably to lock said outer and inner tubes against relative axial movement; a tiring pin slidably accommodated in said ""hinner tube and interengaging with said latch, said firing apin serving to retain said latch in the locking position when that pin is in one position and While the pin is being moved to another position, serves to movesaid latch so as to unlock said outer and inner tubes for relative axial movement and also to act on said explosive cartridge in sequence to cause release of the cartridges energy; and initiator means selectively operable to supply energyto move said ring pin from one position to the other position; whereupon said outer and inner tubes are moved apart axially by said explosive cartridges released energy, resulting in movement of the hatch cover from the hatchway. t

6. The combination, in a device for moving a hatch cover from a hatchway in time of emergency, of an outer tube closed at one end, but open at the opposite end, and adapted for connection to the hatchway; an inner Vtube slidably accommodated in said outer tube for axial movement relative thereto'through the outer tubes open end; a cap also slidably supported in said outer tubes Vopen end, said cap being attached to and closing theend of said inner tube proximal said outer tubes open end, part of said cap extending outside said outer tube and being adapted for connection to the hatch cover; an explosive cartridge in said inner tube for supplying energy to move said inner tube and cojoined cap axially relative to said outer tubes open end thereby to move the hatch cover from the hatchway; a latch in said cap for releasably locking said cap and said outer tube against relative -axial movement thereby also preventing relative axial movement between said outer and inner tubes; a firing pin slidably accommodated in said cap and interengaging with said latch for holding said latch in position to maintain said cap and said outer tube locked against relative axial movement while that pin is in a first position, but said tiring pin'being selectively movable to a second position to move said latch so as to unlock said cap and said outer tube forrelative axial movement and consecutively to act on' said explosive cartridgeV to cause release of the cartridges energy; and an initiator for supplying suficient energy in uid form to said tiring pin to cause that pins movement from the tirst to the second position; whereupon said outer tube and said inner tube and cojoined cap are moved apart axially thereby moving the hatch cover from the hatchway.

7. The combination of claim 6 plus a plug seated in the inner tubes end between that tube and the cap, said plug serving to slidably support a portion of the tiring pin, to aid in positioning the explosive charge, and to aid in slidably supporting the latch.

8. The combination of claim 6 plus a spacer sleeve in the inner tube, said spacer sleeve serving to hold the explosive cartridge in the inner tube.

9. The combination of claim 8 plus retaining means for holding the spacer sleeve in position in the inner tube. 10. In a device for moving a closure from an opening in a Wall, the combination of: an outside tube closed at one end, but open at the opposite end, and adapted for connection to the wall; an inside tube also closed at one end, but open at the opposite end and slidably fitting open end foremost into said outside tube, the closed end of said inside tube being adapted for connection to the closure; an explosive cartridge in said inside tube for supplying energy to move said outside and said inside tubes axially apart from each other so as to move the closure from the opening; a spacer sleeve in said inside tube for positioning said explosive cartridge therein; a plurality of interiitting latches in said inside tube for releasably locking said outside and said inside tubes against relative axial movement; a tiring pin in saidy inside tube normally interengaging said latches to prevent their unlocking said outside and inside tubes, said pin being Vselectively movable into detonating contact with said explosive cartridge and during such movement serving to move said latches so as to unlock the tubes and permit their relative axial movement; and initiator means selectively operable to supply energy for moving said firing pin from its normal to its cartridge detonating position; whereupon said outside and. said Ainsidetubes are. moved axiallyapart Aby theenergy thusxliberated from said explosive cartridge with consequent movement of the closure from. the. opening.

11. In-a device for moving the canopy from the cockpitopening of an airplane in time of emergency, the combination of an external tube; a-irirstcap closing one end of said external tubeand adapted for mounting in the cockpit; an internal tube slidably accommodated in said external tube for axial movement relative thereto through the external tubes open end; a bearing tube in'said external tubes open endfor slidably supporting said internal tube therein; astop ring also in said external tubes open end, said stop ring defining yan annular groove inside said external tube-in .conjunction with vsaid bearing tube; a sealing member in said bearing tube for sealing the space bef tween that tubes interior. surface and said internal tubes exterior surface; a plug seated againstsaid internal tubes end farthermost from said rst cap, part of said plugV extending outside that endof'said internal tube; a second cap, this cap being attached to said internalftube and tting over said plug to close that end'V of said internal tube, part of this cap being. slidably-accommodated in said bearing tube and in said stop ring ywhile the balance of this cap extends outside said external tubes open end and is connected to the canopy; an explosive cartridge in. said internal tube abutting `said plug; said explosive cartridge serving to supply suicient energy to move said external tube and said internal tube and cojoinedsecond cap axially apart so as tomove the canopy from the. cockpit opening; a spacer sleeve in saidinternalrtube for positioning said explosive cartridge; a-retaining spring in. said internal tube for holding saidspacer sleeve in abutment with said explosive cartridge; a pluralityof intertting latches partly in said plug and partly in said Vsecond cap for releasably locking that cap andvsaidl external'rtube against relative axial movement by engagingwith the an- -nular groove vformed byrsaid bearing tube and said stop ring; .a ring'pin slidably accommodated partly in said second cap, partly in said plug, said tiring pin normally interengaging said latches to prevent their unlocking said external tube and said cap, said pin being selectively movable into. detonatingcontact with said explosive cartridge and during suchmovement serving to move said latches .so as to unlock the externaltube and the cap to permit .their relative axial movement; a sealing ring on said tiring pin to slidably seal the space between that pins exterior surface and said second caps supporting surface therearound; a plurality of shear pins partly in said second cap, said internal tube, said, plug and said ringpin for retaining, said .second cap -on said internal tube,y forretaining said plug in position with relation to said second cap, for temporarilyholding said firing pin in the first position and also .for preventing that pin from acting. ou said explosive. cartridge until those. pins are stressed to failuregand aninitiator selectively, operable to supply suicient energy to. said firing pin to cause failure of said shear pins, then to. move. said ring pin from the lirst to the second position; whereupon said'external tube andsaid internal tube and cojoined'second cap are moved axially .apart by said explosive cartridgeis released energy thus moving thev cover from the cockpit opening.

VReferences yCited inthe tile of this patent UNITED .STATES PATENTS Great Britain --.May 9, 1948 

